Recently, with the increasing development of information industries, portable information devices such as notebook computers, mobile phones or personal digital assistants are possibly used in various environments. In case that a portable information device is used in a dim environment, the numbers and the characters marked on the keys of the keyboard of the portable information device are not clearly visible. In other words, the dim environment becomes hindrance from operating the keyboard. In addition, if the numbers and the characters marked on the keys of the keyboard are reluctantly viewed in the dim environment, the user is readily suffered from vision impairment. For solving these drawbacks, a luminous keyboard has been disclosed. The luminous keyboard can be used in the dim environment in order to increase the applications thereof. By changing the layout of the luminous regions of the luminous keyboard, the information device having the luminous keyboard is more aesthetically-pleasing and thus the marketing competiveness is enhanced. Moreover, according to some specified professional demands (e.g., electronic sports demands), the keyboard generates identical light color or different light colors to indicate the keys of the keyboard. Consequently, the keyboard brings better operating efficacy to the user.
Please refer to FIGS. 1, 2 and 3. FIG. 1 is a schematic side view illustrating a conventional luminous keyboard. FIG. 2 is a schematic exploded view illustrating a membrane wiring board of the conventional luminous keyboard of FIG. 1. FIG. 3 is a schematic exploded view illustrating a key structure of the conventional luminous keyboard of FIG. 1. The luminous keyboard of FIG. 1 is designed according to a professional demand such as a gaming demand. The conventional luminous keyboard 1 comprises a metallic base plate 13, a membrane wiring board 14, plural key structures 15 and plural light-emitting elements 16. The membrane wiring board 14 comprises a lower wiring plate 141, an upper wiring plate 142, and an intermediate plate 143. The intermediate plate 143 is arranged between the lower wiring plate 141 and the upper wiring plate 142. The lower wiring plate 141 comprises a first circuit pattern 1411. The first circuit pattern 1411 comprises plural silver paste conductor lines 14111 and plural lower contacts 14112. The upper wiring plate 142 comprises a second circuit pattern 1421. The second circuit pattern 1421 comprises plural silver paste conductor lines 14211 and plural upper contacts 14212. The intermediate plate 143 comprises plural perforations 1431 corresponding to the plural lower contacts 14112 and the plural upper contacts 14212, respectively. Each of the upper contacts 14212 and the corresponding lower contact 14112 are collectively defined as a membrane switch 144.
The metallic base plate 13 is disposed under the membrane wiring board 14. The plural key structures 15 are connected with the metallic base plate 13. The plural key structures 15 are aligned with the corresponding membrane switches 144. Each key structure 15 comprises a keycap 151, a connecting element 153 and an elastic element 152. The connecting element 153 is connected between the corresponding keycap 151 and the metallic base plate 13. Consequently, the keycap 151 is movable upwardly or downwardly relative to the membrane wiring board 14. The elastic element 152 is arranged between the corresponding keycap 151 and the membrane wiring board 14. Moreover, the elastic element 152 comprises a sustaining part 1521.
As the keycap 151 of any key structure 15 is depressed and moved downwardly relative to the membrane wiring board 14, the elastic element 152 is compressed by the keycap 151. Consequently, the corresponding upper contact 14212 of the membrane wiring board 14 is pushed by the sustaining part 1521 of the elastic element 152. Moreover, the upper contact 14212 is contacted with the corresponding lower contact 14112 through a corresponding perforation 1431. In such way, the corresponding membrane switch 144 is electrically conducted, and the membrane wiring board 14 generates a corresponding key signal. When the depressing force exerted on the keycap 151 is eliminated, an elastic force provided by the elastic element 152 is acted on the keycap 151. In response to the elastic force, the keycap 151 is moved upwardly and returned to its original position.
The plural light-emitting elements 16 are aligned with the corresponding key structures 15. That is, one light-emitting element 16 is disposed under one key structure 15. Each light-emitting element 16 emits light beams L1 to the keycap 151 of the corresponding key structure 15. Moreover, the light beams L1 are outputted from plural light-transmissible regions 1511˜1514 of the keycap 151 to produce the illuminating efficacy.
However, the conventional luminous keyboard 1 still has the following drawbacks. For example, the location of the light-emitting element 16 is restricted by the locations of the connecting element 153 and the elastic element 152 of each key structure 15. That is, the location of the light-emitting element 16 is deviated from the center of the key structure 15. Since the location of the light-emitting element 16 is deviated, the luminous uniformity of the conventional luminous keyboard is usually unsatisfied. For example, if the light-emitting element 16 is directly under the light-transmissible regions 1511 and 1512, the light-transmissible regions 1511 and 1512 are much brighter than the light-transmissible regions 1513 and 1514. In other words, the conventional luminous keyboard needs to be further improved.